Method of and apparatus for the matching of colors.



M. R. PEVEAR. METHOD OF AND APPARATUS FOR THE MATCHING 0F COLORS.-

APPLIOATION FILED JULY 16 1914.

Patented Mar. 9, 1915.

ltd

hit

ilt

MUNRGE R. IPEVE, 0F BOSTON, MASSACHUSETTS.

METHOD OF AND APPARATUS FOR THE MATCHING: 0F COLORS.

' Specification of Letters Patent.

mamas mar. a, rare.

Application filed July 16, 19M. Serial No. 851,296.

To all whom it may concern:

Be it known that 1, Monroe R. PnvnAn, a citizen of the United States,residing at Boston, in the county of Suflolk and State of Massachusetts,have invented a certain new and Improved Method of and Apparatus forMatching of Colors, of which the following is a specification, referencebeing had to the accompanying drawings, forming part thereof.

This invention has reference to an improved method of matching colorsand in the apparatus whereby said method is carried into efl'ect.

, Une object of the invention is to supply a beam of light of standardcolor value and to provide for the reflection of said light in gradeddegrees whereby the color under inspection can be compared with variousgrades of reflection.

Another object of the invention is to provide apparatus for carryingthis invention into practice.

The invention consists in providing a beam of light of standard colorand in so refleeting said light in the presence of the color underinspection to determine the percentage flected color appearanceequivalent to the color under inspection and noting the percentage ofreflection required to produce said color appearance.

The invention also consists in providing means graded between absoluteblack and absolute white adapted to reflect relatively to their gradesthe light of a standard color.

The invention also consists in such other novel features in the methodfor matching colors and in the apparatus for carrying out such method asshall hereinafter be more fully described and pointed out in the claims.

Figure 1, represents a series or group of electric lamps having bulbseach of one of the'primary colors which lamps are adapted for use incarrying this invention into practice. Fig. 2, represents a group ofcharts or devices graded as to their capacity for refleeting light frompure white to a pure or absolute black which latter defines the minuslimit or zero of reflection or, as a matter of fact,-the completeabsorption of light received thereby. Fig. 3, represents a moditiedconstruction of a device for supplying color light beams.

of reflection necessary to produce from said light beam of standardcolor a retransmit color rays of one of the primary colors. ll preferthat said light sources should be a series of electric incandescentlamps having bulbs of suitable color. When but three of the lightsources are used their bulbs are colored respectively red, green andblue as by a combination of these colors under illumination any colorappearance or shade of color appearance may be produced. When it makeuse of more than three light sources ll prefer to use six of the primarycolors.

As shown in Fig. 1 of the drawing the electric incandescent lamps A, B,G, D, E, and 15 have bulbs or globes respectively of the colors red,green, blue, yellow, purple and orange andelectric current is suppliedto said lamps from the generator G or other source of electric energythrough the leads w, 31 and branch circuits connecting said leads or, ywith the respective lamps and having respectively the switches orcircuit closers'w, b, c, d, e and f. With such series of color lightsources I am enabled to provide color light beams of a known standard ofcolor on to an object or article to be tested or matched. I

Having thus provided for a series of color light beams or colorappearance of known standard ll now provide a series of charts, cards orother devices of any suitable number but preferably ten or multiples often graded progressively from pure white as representing the mostperfect light reflection to pure black as representing the most completelight absorption or minus reflection. The gradings of these reflectionscreens, charts or devices 1, 2, 3, 4, 5, 6, 7, 8,

9, and 10 are by shadings of pure black and white to avoid variation ofthe color appearance, reflected thereby from the color of the light beamwhile also providing for the reflection of only such proportionatedegree of said color appearance of the light beam as is not absorbed bythe particular chart in use. ()bviously by increasing the number ofcharts shown in Fig. 2 of the drawing the grades of light absorption orreflection may be increased accordingly and for convenience saidcharts-may be graded according H0 to their percentage of lightabsorption or conversely of their several capacities to reflectlight, Ifnow the beam of light from lamp A is thrown on the color to be matchedor inspected for any color comparison and chart 5 is placed beside saidcolor under inspection the color appearance reflected by said chart 5will contain fifty per cent. of the color standard of the light beamthrown by saidlamp A. If, by comparison of the color sample with thecolor appearance thus refiected from chart'5, it is found that saidcolors of said sample and reflected color appearance match, it isapparent that said sample contains fifty per cent. of red, the color, oflamp A and said information may be noted for future use. Similarly thesame sample may be compared with the light beams from any other of saidlamps A to F inclusive with the ultimate result that all the colorscontained in said sample and the proportionate of said colors are known.

In Fig. 3 is shown diagrammatically a room or chamber having a partitionH furnished with openings having the .colored light screens red, blueand green which are illuminated by comparatively white lights L,L of anykind placed back of said partition H. With this device the sample to bematched or inspected is placed in the inspection compartmentI whichpreferably is large enough to permit the entrance therein of the personmah'ng the comparison.

It is of course obvious that all of the charts shown in Fig. 2 or anysimilar charts may be associated in a single chart having areas shadedprogressively from pure white to pure black. And it is apparent that bythe use of a sufiicient number of said graduations of shadings from purewhite to pure black and by the comparison of the color appearancereflected by certain of said graduated shadings with the color of thesample the exact proportion of the particular-color contained in saidsample may be ascertained.

Having thus described my invention I claim as new and desire to secureby Letters Patent- 1. The method of matching colors which consists inprojecting a color light beam of known color standard on to the sampleunder inspection, and comparing the color appearance thereofwith aseries of standard graded light absorption devices to determine theamount of said color appearance necessary to be eliminated to reducesaid color appearance to the equivalent of said sample.

2. Apparatus for matching colors comprising means for producing a lightbeam of known color standard and a series of devices graded as to theircapacity to absorb color from said 1i ht beam.

HENRY J. MILLER, Es'rHnR C. MURPHY.

